IOK vs pIOK docs

Date: Thu, 7 Jun 2001 10:09:59 +0100 (BST)
Reply-To: Dave Mitchell <davem@fdgroup.co.uk>
Message-Id: <200106070909.KAA25610@gizmo.fdgroup.co.uk>

p4raw-id: //depot/perl@10468

diff --git a/pod/perlguts.pod b/pod/perlguts.pod
index 3fea294..aa5de9f 100644 (file)
--- a/pod/perlguts.pod
+++ b/pod/perlguts.pod
@@ -274,6 +274,14 @@ pointer in an SV, you can use the following three macros instead:
 These will tell you if you truly have an integer, double, or string pointer
 stored in your SV.  The "p" stands for private.
 
+The are various ways in which the private and public flags may differ.
+For example, a tied SV may have a valid underlying value in the IV slot
+(so SvIOKp is true), but the data should be accessed via the FETCH
+routine rather than directly, so SvIOK is false. Another is when
+numeric conversion has occured and precision has been lost: only the
+private flag is set on 'lossy' values. So when an NV is converted to an
+IV with loss, SvIOKp, SvNOKp and SvNOK will be set, while SvIOK wont be.
+
 In general, though, it's best to use the C<Sv*V> macros.
 
 =head2 Working with AVs